1) Field of the Invention
This invention relates to a device for the simulation of a rod-shaped virtual surgical instrument, in particular for the simulation of an endoscopic instrument, for the generation of a feedback signal, with a sleeve in which a push rod is located.
2) Description of the Related Art
A force feedback is almost always used in a device for use in the simulation of surgical procedures, in particular endoscopic surgeries, to provide a simulation for the operator of the resistance encountered by the instrument as it penetrates tissue or comes into contact with internal organs and other elements. When clamps or scissors are to be used, the operator thereby uses a corresponding scissors-shaped handle of a simulated instrument which simulates the actual handle. Generally, a spring is then located between the handle parts of the pair of scissors, as on the actual instrument, against the resistance of which the handles of the scissors can be compressed.
This device of the prior art has the disadvantage that when the surgeon is cutting through tissue, after the cut, it should be possible to close these scissors without encountering any significant additional resistance, which cannot be realized with the spring that is used in the devices of the prior art. Furthermore, when a virtual clamp of the type described in the prior art is used, during the actuation of the handle a resistance can be felt directly that does not increase as the simulated clamping action begins to increase, and in particular does not vary as a function of the tissue on the basis of the elasticity of the tissue to which the force is being applied. The prior art also discloses a variety of additional simulated surgical instruments that are used in endoscopic procedures. Most of these instruments have a handle in the form of a scissors-type handle, by means of which the user performing the simulation can clamp, grip or cut something. In these devices of the prior art, one half of the scissors can be moved against a spring tension, so that an increasing pressure is transmitted to the user as the halves of the scissors close.
The devices of the prior art have a number of disadvantages, in particular the fact that unrestricted movement is not suddenly restored when the scissors have cut all the way through a simulated object. Furthermore, there is no ability to simulate the impact of the simulated element against an inflexible or inelastic resistance.